When receiving messages from external systems or sending messages to external systems, the external headers of the messages can be mapped to and from Ditto protocol headers.
That way the headers can be passed through Ditto, or defined Ditto protocol headers like for example
correlation-id may be
mapped to a header used for message correlation in the external system.
The supported placeholders for header mapping are defined in the Placeholders - Scope: Connections section. If a placeholder fails to resolve for a header value, then that header is not set. Placeholder resolution failure does not prevent sending of the message or setting other headers with resolved values.